doc: harmonize YAML comments style in deprecations.md

Refs: nodejs/remark-preset-lint-node#139

PR-URL: nodejs#35454
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ujjwal Sharma <ryzokuken@disroot.org>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Michael Dawson <midawson@redhat.com>